Like “A-Tisket, A-Tasket”, if you grew up in the English-speaking world, you are probably familiar with “Ring Around the Rosie”. The version I learned goes:

Ring around the rosie,
Pocket full of posies,
Ashes, ashes,
We all fall down.

…followed by everyone in the room falling on their rumps. (That was hi-lairious to me at a certain young age.)

I remember watching an episode of “Ripley’s Believe It or Not” (with Jack Palance!) sometime in the mid-1980’s, and learning that this seemingly innocent children’s rhyme was apparently some sort of code for the horrors of the bubonic plague. “Rosie” referred to the boils, the posies referred to flowers placed on coffins, falling down referred to death… you know, just exactly the dark, fascinating stuff that sticks in a nerdy kid’s mind.